Responding to threat quickly and efficiently is critical for survival. Indeed, when faced with the approach of a slithering snake or a dangerous drop-off, delays in responding can be costly, perhaps even deadly. But how do we learn what is safe and what is dangerous? How do we detect and respond to potential threats—dangerous animals, aggressive people, infectious diseases—in the world around us?
Because of the significant reproductive benefit associated with rapid identification of threatening stimuli, the most prominent theories propose that humans have evolved psychological mechanisms that facilitate the detection and subsequent avoidance of potential threat. These mechanisms are thought to detect cues in the environment that signal the presence of threat, and initiate cognitive and emotional responses that lead to avoidance behavior.
For example, researchers have proposed that humans possess an evolved fear module that is activated upon contact with recurrent, widespread, and evolutionarily relevant threats like snakes, spiders, and threatening conspecifics; activation of this module is automatic, and leads to rapid detection and rapid fear learning for threatening stimuli (Öhman & Mineka, 2001, 2003). Behavioral immune system theory proposes that a similar set of mechanisms evolved to detect the presence of pathogens or infectious illness, automatically activating disgust responses that result in avoidance behavior (e.g., Murray & Schaller, 2016; Oaten, Stevenson, & Case, 2011; Schaller & Park, 2011). Although these and other similar theories differ in their specifics, they all assume that humans possess a specialized set of mechanisms for threat detection and avoidance that are universal, early emerging, and stable across individuals. However, until recently, no developmental research had addressed this topic.
My research program investigates human behavioral responses to emotionally valenced stimuli—specifically to negative or threatening stimuli—and the mechanisms guiding the development of these responses. In one line of research, I found that humans perceive the presence of threatening stimuli very quickly, and that rapid detection begins in infancy. However, these biases can be learned, they can change over the course of development, and may reflect a broad spectrum of individual differences. Further, in a second line of research, I found that avoidance responses to threats do not develop until later in childhood, and are dependent on learning. My current work builds on these findings to ask whether early perceptual biases for threat contribute to maladaptive avoidance behaviors, such as those associated with the development of fear and anxiety, and how children learn adaptive avoidance responses, such as avoidance of contagious people or contaminated objects. Altogether, my findings suggest that human threat responses are not singular or automatic: They are differential and complex, supporting flexible developmental trajectories based on both experience and context. By continuing to develop procedures that measure threat responses developmentally, and by establishing the developmental time course of these behaviors, I hope to create a broader theoretical framework for understanding how early developing biases for threat interact with everyday experience to create both adaptive and maladaptive patterns of responding.